Li-Fi is a wireless optical networking technology that uses light-emitting diodes (LEDs) for data transmission. It was first suggested in 2011 as an alternative to Wi-Fi and has since been proven as a viable technology. Li-Fi transmits data using visible light communication between an LED light bulb and a photodetector. It provides advantages over Wi-Fi such as better security since light cannot pass through walls, higher speed potential, and no radio interference. Main applications of Li-Fi include smart lighting, vehicle transportation, hospitals, and underwater communications.

1. LIFI-LIGHT FIDELITY
LIFI-LIGHT FIDELITYLIFI-LIGHT FIDELITY
Submitted By:
VISHAL KASANA
1513331227
IT 2nd Year
Submitted To:
MR. SOMESH KUMAR
MR. AMARPAL YADAV

2. Content
• Introduction
• History
• How Li-Fi Works?
• Wifi vs lifi
• Application
• Advantages
• Disadvantages
• Conclusion

3. Introduction
• Light Fidelity or LiFi is a wireless optical networking technology that uses
light-emitting diodes (LEDs) for data transmission.
• LiFi is designed to use LED light bulbs similar to those currently in use in
many energy-conscious homes and offices.
• However, LiFi bulbs are outfitted with a chip that modulates the light
imperceptibly for optical data transmission.
• LiFi data is transmitted by the LED bulbs and received by photoreceptors.

4. History
• In 2011, Professor Harold Haas from the University of Edinburgh in
the UK, suggested an idea called “Data through illumination” .
• He coined the term Li-Fi during his TED Global talk.
• The first Li-Fi smartphone prototype was presented at the Consumer
Electronics Show in Las Vegas from January 7–10 in 2014.
• Li-Fi is no longer a concept or an idea but a proven technology.
Already, several experts in the field of
communication have attested that
Li-Fi technology would soon become a
standard adjunct to Wi-Fi.

5. How Li-Fi Works?
• Li-Fi and Wi-Fi are quite similar as both transmit data electromagnetically.
However, Wi-Fi uses radio waves while Li-Fi runs on visible light.
• As we now know, Li-Fi is a Visible Light Communications (VLC) system. This means
that it accommodates a photo-detector to receive light signals and a signal
processing element to convert the data into binary.
• An LED is a semi-conductor, it is an electronics device it have a very nice property
that its intencity can be modulated at a very high speed and it can be switched off
and on at a very high speed, without being visible to the human eye, which is used
as binary input, this is the fundamental technology of LiFi
• For example, data is fed into an LED light bulb (with signal processing technology),
it then sends data (embedded in its beam) at rapid speeds to the photo-detector
(photodiode).
• The tiny changes in the rapid dimming of LED bulbs is then converted by the
'receiver' into electrical signal.
• The signal is then converted back into a binary data stream that we would
recognise as web, video and audio applications that run on internet enables
devices.

8. Transmitting Elements
• LED Fluorescent Lamp

9. Receiving Elements
• Photo Diode Image Sensor

10. LIFI VS WIFI
Feature LiFi WiFi
Full form Light Fidelity Wireless Fidelity
Operation
LiFi transmits data using light
with the help of LED bulbs.
WiFi transmits data using radio
waves with the help of WiFi
router.
Interference
Do not have any intereference
issues similar to radio frequency
waves.
Will have intereference issues
from nearby access
points(routers)
Applications
Used in airlines, undersea
explorations, operation theaters
in the hospitals, office and home
premises for data transfer and
internet browsing
Used for internet browsing with
the help of wifi kiosks or wifi
hotspots
Merits(advantages)
Interference is less, can pass
through salty sea water, works in
densy region
Interference is more, can not
pass through sea water, works in
less densy region

11. Privacy
In LiFi, light is blocked by the
walls and hence will provide
more secure data transfer
In WiFi, RF signal can not be
blocked by the walls and hence
need to employ techniques to
achieve secure data transfer.
Data transfer speed About 1 Gbps
WLAN-11n offers 150Mbps,
About 1-2 Gbps can be achieved
using WiGig/Giga-IR
Frequency of operation
10 thousand times frequency
spectrum of the radio
2.4GHz, 4.9GHz and 5GHz
Data density Works in high dense environment
Works in less dense environment
due to interference related issues
Coverage distance About 10 meters
About 32 meters (WLAN
802.11b/11g), vary based on
transmit power and antenna type
System components
Lamp driver, LED bulb(lamp) and
photo detector will make up
complete LiFi system.
requires routers to be installed,
subscriber
devices(laptops,PDAs,desktops)
are referred as stations

12. Applications
• SMART LIGHTING
• VEHICLE & TRANSPORTATION
• HOSPITALS & HEALTHCARE
• Underwater Communications
• Security
• AVIATION
• Toys
• ETC…

13. SMART LIGHTING
• Any private or public lighting including street lamps can be used to
provide Li-Fi hotspots and the same communications and sensor
infrastructure can be used to monitor and control lighting and data. Smart
buildings require smart lighting. Smart lighting with VLC provides the
infrastructure for illumination, control and communications and will
greatly reduce wiring and energy consumption within a building.

15. VEHICLE & TRANSPORTATION
• Many cars already LED lamps. Traffic signage, traffic lights, and street lamps are
adopting the LED technology so there are massive applications opportunities
here.

16. HOSPITALS & HEALTHCARE
• There are advantages for using VLC in hospitals and in healthcare. Mobile
phones and WiFi’s are undesirable in certain parts of hospitals, especially
around MRI scanners and in operating theatres. Li-Fi emits no
electromagnetic interference
and so does not interfere with
medical instruments, nor is
it interfered with by MRI
scanners.

17. Underwater Communications
• Due to strong signal absorption in water, RF use is impractical.
Acoustic waves have extremely low bandwidth and disturb marine
life. Li-Fi provides a solution for short-range communications.

18. Security
• In a meeting room environment, the access area of each channel is
the width of the light pool, and can be accessed by multiple users.
Each user can receive higher data rates than would be the case for an
equivalent Wi-Fi channel. In the Wi-Fi case, each user or group of
users directly competes for access to bandwidth. The net result is that
the more connections there are, the slower the download speeds are
for all. By contrast, in the case of Li-Fi, with its greater number of
available access points, each pool of light provides full channel data
rates with fewer simultaneous users. The overall net benefit to each
user is up to 1000 times greater speeds. In addition, and in contrast
to radio waves, the light does not pass through the walls. Therefore,
with minimal precautions to avoid leakage from windows, etc.,
security is fundamentally enhanced as compared with Wi-Fi.

19. AVIATION
• Li-Fi can be used to reduce weight and cabling and add flexibility to
seating layouts in aircraft passenger cabins where LED lights are
already deployed. In-flight entertainment (IFE) systems can also be
supported and integrated with passengers’ own mobile devices.

20. Toys
• Many toys incorporate LED lights and these can be used to enable
extremely low-cost communication between interactive toys.

21. Advantages of LI-FI
• Li-Fi can solve problems related to the insufficiency of radio
frequency bandwidth because this technology uses Visible light
spectrum that has still not been greatly utilized.
• High data transmission rates of up to 10Gbps can be achieved.
• Since light cannot penetrate walls, it provides privacy and security that
Wi-Fi cannot.
• Li-Fi has low implementation and maintenance costs.

22. Disadvantage
• Light can't pass through objects.
• A major challenge facing Li-Fi is how the receiving device will
transmit back to transmitter.
• High installation cost of the VLC systems.
• Interferences from external light sources like sun, light, normal bulbs,
opaque materials.

23. Conclusion
• The possibilities are numerous and can be explored further. If his
technology can be put into practical use, every bulb can be used something
like a Wi-Fi hotspot to transmit wireless data and we will proceed toward
the cleaner, greener, safer and brighter future. The concept of Li-Fi is
currently attracting a great deal of interest, not least because it may offer a
genuine and very efficient alternative to radio-based wireless. As a growing
number of people and their many devices access wireless internet, the
airwaves are becoming increasingly clogged, making it more and more
difficult to get a reliable, high-speed signal. This may solve issues such as
the shortage of radio-frequency bandwidth and also allow internet where
traditional radio based wireless isn’t allowed such as aircraft or hospitals.

24. References
• www.wikipedia.com
• www.google.com
• The.5za9.wordpress.com

26. ???????